21798659 has 4 divisors (see below), whose sum is σ = 21908400. Its totient is φ = 21688920.

The previous prime is 21798653. The next prime is 21798683. The reversal of 21798659 is 95689712.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21798659 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21798653) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 54572 + ... + 54969.

It is an arithmetic number, because the mean of its divisors is an integer number (5477100).

Almost surely, 2^21798659 is an apocalyptic number.

21798659 is a deficient number, since it is larger than the sum of its proper divisors (109741).

21798659 is a wasteful number, since it uses less digits than its factorization.

21798659 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109740.

The product of its digits is 272160, while the sum is 47.

The square root of 21798659 is about 4668.9034044409. The cubic root of 21798659 is about 279.3465160049.

The spelling of 21798659 in words is "twenty-one million, seven hundred ninety-eight thousand, six hundred fifty-nine".